An index of minor physical anomalies will be related to individual differences in the level of androgen and estrogen circulating in cord blood at birth. Previous research has identified both androgenic hormones and the incidence of minor physical anomalies as related to active, aggressive behaviors in young children. In the Stanford Longitudinal Study, under the direction of Drs. Eleanor Maccoby and Carol Jacklin, the neonatal hormonal assays for this group of children have been collected. As part of the follow-up of these children at age 18 months, the presence of minor physical anomalies have been assessed. Analyses will be conducted to see if the anomaly index is related to the level of sex hormones present at birth. If anomalies index the level of masculinizing testosterone present at birth, an important antecedent of the incidence of multiple minor physical anomalies as well as the mechanism which would explain the relations found previously between active, aggressive behaviors and anomalies will have been identified.